This invention relates to a rectifier device in a vehicle AC generator, which converts alternating current generated by the generator into direct current.
FIG. 4 is a sectional view showing a vehicle AC generator equipped with a conventional rectifier device. In FIG. 4, reference numeral 1 designates a stator comprising a stator core 2, and a stator coil 3 wound on the stator core; 4, a rotor comprising a pair of magnetic pole cores 5 and 6 confronted with each other, an exciting coil 7 interposed between those cores 5 and 6, a rotary shaft 8, and slip rings 9 fixedly mounted on the rotary shaft 8 in such a manner that the former are electrically insulated from the latter; 10 and 11, fans mounted on the magnetic pole cores 5 and 6, respectively; 12, a front bracket supporting the stator 1, the front bracket 12 having air sucking holes 12a and air discharging holes 12b; 13, a rear bracket having air sucking holes 13a and air discharging holes 13b, the rear bracket 13 being secured to the front bracket 12 with tightening bolts 14 in such a manner that the stator core 2 is held between the front bracket 12 and the rear bracket 13; 15 and 16, bearings through which the front bracket 12 and the rear bracket 13 support the rotary shaft 8; and 17, a pulley fixedly mounted on one end portion of the rotary shaft 8, the pulley 17 being coupled through belt means to the engine.
Further in FIG. 4, reference numeral 18 designates the rectifier device connected through lead wires to the stator coil 3, the rectifier device 18 adapted to convert polyphase alternating currents into a direct current which is supplied to a DC load such as a battery; and 19, a voltage regulator mounted on the rear bracket together with a brush holder 20. The voltage regulator 19 detects the output voltage of the generator to control the exciting current thereby to maintain the supply terminal voltage at a predetermined value. The brush holder 20 supports brushes 21 in such a manner that the brushes 21 are held pushed against the slip rings 9.
As shown in FIG. 5, a front view of the inside of the rear bracket 13, the rectifier device 18 is mounted on the rear bracket 13 with mounting screws 31a and 31b . In order to receive the mounting screws 31a and 31b the rear bracket 13 has arcuate protrusions 13c extended radially outwardly therefrom. The brush holder 20 together with the voltage regulator 19 is mounted on the rear bracket 13 with mounting screws 34. The slip rings 9 are surrounded by a cylinder 20 of synthetic resin which is formed integral with the casing of the brush holder 20. A connector 23 is provided in a frame which is formed integral with the casing of the brush holder 20.
The rectifier device 18 is shown in FIG. 6 in more detail. A positive (+) side heat sink 27 (cf. FIG. 7) with positive (+) side diodes 25, and a negative (-) side heat sink 28 (cf. FIG. 7) with negative (-) side diodes 26, together with a wiring board 30, are mounted on the rear bracket 13 with the mounting screws 31a and 31b . The rectifier device 18 further includes three auxiliary diodes 32, and a capacitor 33.
The heat sinks equipped with the diodes as shown in FIG. 6 are illustrated in the parts (A) and (B) of FIG. 7, which are a front view and a side sectional view, respectively. As is apparent from FIG. 7, the diode mounting seats of the heat sinks 27 and 28 are flush with each other and extended parallel with each other. The heat sink 27 has a number of cooling fins 27a , and the heat sink 28 also has a number of cooling fins 28a . The heat sinks 27 and 28 have mounting holes 29a and 29b.
In the conventional rectifier device thus constructed, the diode mounting seats of the heat sinks 27 and 28 are flush with each other as was described above, and in order for the heat sinks to have sufficient heat radiating areas, their length L is necessarily long, and accordingly arcuate protrusions 13c of the rear bracket 13 are unavoidably large. This structure may obstruct the mounting of the AC generator on the engine.